Yes, in the interface. The computer works only with digital bits not analogue signals, so the analogue world gets converted into a digital form in the interface for the computer to munch on, and then converted back when the computer spits out the answers.

awjoe wrote:Where does A/D D/A conversion happen - in the interface, or in the CPU? And does it matter?

FWIW, I'm getting a new interface, and I think it's going to be a Presonus Studio 26.

The interface has connections for the audio signal and somewhere on the circuit board inside there will be an Integrated Circuit (IC) that converts between analogue signals and digital ones. Something like this. ICs like these have pins for the audio analogue data and digital data and convert between the two.

The interface can communicate the audio digitally to a computer using the USB connection, the CPU in a computer can only work on digital data (formed of bits that are 1 or 0) although these are represented by voltages those voltages are only interpreted as 1 or 0.

I decided to ask for two reasons, the first being that one of the specs for the Presonus interface is '32 GB of hard disk space' and it got me wondering what happens on the computer side of things when A's are getting converted to D's. Hugh and wireman made it clear - the computer can't deal with analogue.

Also, I wondered how long it would take for the first jokes to come in after my straight line.

I'd suggest that 32GB is a provision to ensure the software loads smoothly and runs well. If you've got less free space on your disk before loading, then you could be filling a lot of that up. And a lot of operating systems need a reasonable amount of space in order to move files around and for cacheing. If the amount of free space drops too far, then the computer can seriously slow down, making DAW use problematic.